The 26-year-old Swedish international midfielder, whose contract with Blues expires at the end of the month, will join up once again with Blues boss Steve Bruce at The Stadium of Light on 1st July as a free agent.
"I had other alternatives but it's great to sign with a club like Sunderland," said Larsson.
"Steve Bruce showed he really wanted me and that's important.
"Sunderland are building for the future and want to be better than last year."